MustangWorks.com : Ford Forums - View Single Post - How does a person with 4.56's and an AOD end up with a calibrated speedo?

crazypete · 05-06-2004, 12:00 PM

Here's how I chose the gear:

My original 1987 ford mustang lx 5.0 pulled about 3000 rpms going 75 on 25.5 inch tires (r15's). I later found out that I had been driving around on 3.73's for years and didnt even know it. I just figured 5.0's were all high revvers till I rode in a 2.73 equipped stang and saw how low that dudes rpm's were! I liked that rpm band for highway cruising and wanted my highway umph back. When you stabbed the throttle, you were already in the power band and the car just took off! Right now, even with 3.73's, she churges around at 2000 rpms at 60 and really just fights the gear all the way up to 75 mph when it is at a measly 2400.

Sooooo...

I hit a few calculators.

http://www.4x4cyberstore.com/website/rpmchart.html

With my aod.s .67 OD and my taller 26.6 tires (r16's), I ended up with the 4.56's at the end of the equation.

I patted myself on the back for being _that_ hardcore and walked around feeling hairy chested the rest of the day =P. Alas, I already have the gears, they are sitting in my room. They look sexy! 41 teeth on the ring and 9 teeth on the pinion.

My long term goals are to make the car fast on 'all motor'. I'm not a big fan of spray. It's a consumable resource. It's not really......like......part of the motor, you're just spraying liquid air into your motor to make it work harder. Have you seen how much tubing it takes to set up a good nitruous system. GASP! I spent months cleaning up my enginebay. Longterm, I'm going to add a 3000 stall and some twisted wedge heads and then call the car complete.

What's "N/A trim only", by the way?

05-06-2004, 12:00 PM	#5
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Here's how I chose the gear: My original 1987 ford mustang lx 5.0 pulled about 3000 rpms going 75 on 25.5 inch tires (r15's). I later found out that I had been driving around on 3.73's for years and didnt even know it. I just figured 5.0's were all high revvers till I rode in a 2.73 equipped stang and saw how low that dudes rpm's were! I liked that rpm band for highway cruising and wanted my highway umph back. When you stabbed the throttle, you were already in the power band and the car just took off! Right now, even with 3.73's, she churges around at 2000 rpms at 60 and really just fights the gear all the way up to 75 mph when it is at a measly 2400. Sooooo... I hit a few calculators. http://www.4x4cyberstore.com/website/rpmchart.html With my aod.s .67 OD and my taller 26.6 tires (r16's), I ended up with the 4.56's at the end of the equation. I patted myself on the back for being _that_ hardcore and walked around feeling hairy chested the rest of the day =P. Alas, I already have the gears, they are sitting in my room. They look sexy! 41 teeth on the ring and 9 teeth on the pinion. My long term goals are to make the car fast on 'all motor'. I'm not a big fan of spray. It's a consumable resource. It's not really......like......part of the motor, you're just spraying liquid air into your motor to make it work harder. Have you seen how much tubing it takes to set up a good nitruous system. GASP! I spent months cleaning up my enginebay. Longterm, I'm going to add a 3000 stall and some twisted wedge heads and then call the car complete. What's "N/A trim only", by the way? __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior Last edited by crazypete; 05-06-2004 at 12:20 PM..